Yantai Paper

 

How an owner can prevent falsework collapses

and other construction disasters on its projects

by effective application of the project specification

  

stuart Curtis

RTR Bridge Construction Services

Australia

  

 

Abstract

 

Due to an increasing shortage of skilled personnel at all levels in the construction industry, organisations tend to avoid supplying the necessary supervisors and inspectors to ensure that quality standards are achieved and that construction problems and potential dangers are identified and prevented. Infrastructure owners must recognize the need for effective inspection – and this includes determining who will supply the inspectors and who will pay for their services.

 

Project specifications and contract documents are usually very vague about supervision and inspection requirements and responsibilities; and this vagueness carries over into the contractor’s tender price. However, the new International Execution Standard enables design consultants to effectively specify inspection requirements. This paper explains how.

 

Ineffective specification of inspection requirements has led to countless quality problems and contractual disputes – and occasionally to a disaster such as occurred recently on Can Tho Bridge in Vietnam. This paper explains how the risk of such disasters can be greatly reduced. 

 

This paper advocates a radical change in planning and managing construction projects. However if enough owners and design consultants can respond to this challenge it will produce a change in culture which will not only raise construction standards and save many lives – it will also bring major financial benefits to all sectors of the construction industry 

 

Keywords: inspection, owners, consultants, auditors, specification, disaster, prevention, integrity

 

 

1.  Introduction

 

It is widely acknowledged that there is a growing shortage of available qualified people with the necessary skills and experience to meet the demands of our engineering construction and project management industries. Nevertheless, clients such as infrastructure owners will not delay their funded projects, nor will contractors refuse to tender because they can’t get the people they need to meet specified requirements. (They will do the best they can with the people they can afford.)

 

Also many public sector owners are withdrawing from their traditional inspection role – and yet they are often unwilling to pay for effective inspection by third parties. In this climate, the risk of serious and even catastrophic disaster must be increasing. The recent falsework collapse at the Can Tho Bridge in Vietnam was a wake-up call for the construction industry to put its house in order.

 

The purpose of this paper is to introduce and seek support for the principles of disaster prevention outlined in the paper; and for the formation of an International Joint Task Force (IJTF) to investigate and implement the recommendations outlined in Figure 1 and the relevant text.

 

 

2 Some important background information

 

2.1 Initiatives of fib Bulletin 44

 

Many of the concepts presented in this paper were initially developed in Appendices F and G of the recently published fib Bulletin 44, which is entitled:

 

“Concrete structure management – Guide to ownership and good practice”

 

Appendix F is entitled “Benefits of preconstruction planning” and

 

Appendix G is entitled “Project specifications – An owner’s tool”

 

(While this paper is based on an fib initiative, it recognizes initiatives which have been taken by others - notably FIDIC (International Federation of Consulting Engineers) and ISO (International Standards Organisation). In particular, the new international Execution Standard for the execution of concrete structures, (ISO/DIS 22966}, is a key component of the fib initiative)  

  

2.2 Relevance of the Chinese Construction Law

 

The inter-relationship between quality and safety is acknowledged by the Construction Law of the People’s Republic of China (PRC) – effective from 1997 – which was formulated “with a view to strengthening supervision and regulation of construction activities ….. (and) ensuring the quality and safety of construction projects …..” Furthermore, when the “Regulations on the Quality of Construction Projects” were issued by the PRC Ministry of Construction in 2000, it became even clearer that “quality” also means “safety”.

 

In many ways, the Chinese Construction Law provides a model for other nations to follow. However, if this paper is to achieve its purpose in China, there must be support and participation at a higher level – the State Council. It is hoped that this will be readily forthcoming in view of Articles 43 & 44 of the Regulations, which state that “the administrative department in charge of construction in the State Council shall supervise and administer the quality of the construction projects nationwide in a unified manner” and “shall strengthen the supervision and examination on the implementation of the law, rules and compulsory standards of the corresponding construction projects”.

 

Finally, reference is made to Article 5 of the Regulations, which states that “Construction projects must be carried out strictly in line with the basic construction procedures and stick to the principles of reconnoitering (investigation) firstly, designing secondly, and building finally”.

 

2.3 Owners’ conflict of interest in relation to “traditional” and “design and build” contracts

 

The above-quoted Article from the Chinese Construction Regulations is perfectly consistent with the following quotation from the ASCE Guide, “Quality in the Construction Project”. This statement clearly has the full support of FIDIC. (See FIDIC Guide, “Improving the Quality of Construction” P 10)

 

“Quality in the constructed project is achieved when the project team works together to fulfill their responsibilities to complete the project objectives in a manner that satisfies the requirements of each participant. The agreement between the owner and the professional, and the contract between the owner and constructor are the cornerstones of project quality.”

 

From a quality (and safety) point of view, it is very clear that owners and consulting engineers prefer that thorough investigation and design should be carried out by or on behalf of the owner.

Despite this preference however, there is an increasing tendency around the world, (with the possible exception of the USA), for projects to be contracted as D & B (design and build) or D & C (design and construct) – which are diametrically opposed to the purposes of the traditional contract.

 

The problem is that in many government construction authorities, the quality objectives are usually over-ruled by short-sighted commercial considerations. This includes trying to “shift risk and responsibility away from the client onto the contractor” (See FIDIC Guide P 1)

 

2.4 The importance of quality plans – but not ISO 9001:2000

 

Even QA (Quality Assurance) Contracts usually tend to transfer the responsibility for specifying construction requirements from the owner’s designer to the contractor. Originally, (under the 1987 and 1994 versions of ISO 9001), it was possible for the owner to prepare tender documents which required the contractor to submit a comprehensive quality plan with documented procedures to explain how, where, when and by whom the critical construction processes would be carried out. However, when the 2000 version of ISO 9001 came into operation, it became virtually impossible for the owner to demand documented construction procedures from the contractor.

 

This paper, supported by the detailed information provided in Appendix G of fib Bulletin 44, advocates very strongly the necessity to prepare quality plans for each major sphere of operations. However, ISO 9001:2000 is not appropriate for producing quality plans for the processes involved in concrete work – including falsework erection. The effective specifying of quality plan requirements, as advocated in this paper, can restore to the owner/designer effective management of the project, and at the same time ensure that conscientious contractors are properly rewarded.

 

 

3   Development of the Project Specification

A brief overview is given here of the proposal presented in Figure 1. It will be noted that the proposal aligns itself most easily with the traditional contract approach favoured by FIDIC, ASCE and the PRC State Council. However, it is also designed to be applied to D & B type contracts, in which case the owner prepares an Interim Project Specification (IPS), and this is converted into a Final Project Specification (FPS) by the contractor. (See Nodes N1, N2 and N3 in Figure 1)

 

From a study of Figure 1 it will be seen that quality plans are a central feature of the proposed initiatives. In fact, quality sub-plans should be developed for each major construction process (N6, N7 and N8), such as concreting, post-tensioning and falsework supply and erection.

 

A particular concrete structure type is produced by a combination of processes. For example, the section of superstructure which was being built at Can Tho would have required quality sub-plans for at least the following processes: falsework, post-tensioning, concrete supply, concreting (including formwork and placing of reinforcement) and supply, erection and maintenance of falsework. In addition, there would be a requirement for a separate sub-plan for inspection (including supervision, monitoring and auditing/verification) – unless the inspection requirements were integrated in the sub-plans for construction.

 

By identifying the potential problems in each of the processes (including inspection), and by specifying appropriate requirements to minimize these problems, (see Steps 1-4), a designer (or contractor) can prepare a standard specification for a particular process (Step 5). Such standard specifications (such as are published by some major construction authorities – or industry organizations such as the American Concrete Institute), can be used or combined into a Partial Project Specification (PPS) for a particular bridge type (N9).

 

A primary purpose of this paper is to inspire the proposed Joint Task Force (in cooperation with owners, consultants and contractors on selected projects) to progressively develop and publish an internationally accessible resource library (N4) - with an accompanying Guide (N5) - which will enable owners to produce a comprehensive and contractually effective IPS for a design and build contract – one that will be almost as effective as the equivalent FPS that would be prepared for a traditional contract. If this can be achieved, it will lead to greatly improved tendering practices and greatly reduced risks of quality failures and injury or death during construction operations (N10 and N11)

 

 

 

4  Application of the International Execution Standard

   

4.1 The assumptions – the conflict between desired conditions and the real world

 

In the Execution Standard, Clause 4 is entitled “Execution management”, Clause 4.1 summarises the assumptions which are typically applied to a construction project.  These assumptions include::

  1. the availability of a comprehensive design for the structure”,

  2. “a project management in charge of the supervision of the works which will enable the execution of a conforming structure” and

  3. “a site management which will take charge of the organisation of the works and enable the correct and safe use of equipment and machinery, the satisfactory quality of materials, the execution of a conforming structure and its safe use up to the delivery of the works”. It also presupposes that:

  4. ‘the work is carried out with the necessary skill and adequate equipment and resources to perform the work in accordance with this Standard and the requirements of the execution specification”

There is a tremendous gap between these assumptions and what actually happens – even on traditional contracts, let alone design and build. (Of course design and build projects obviously don’t comply with the first assumption.) Furthermore, phrases such as “necessary skill” and “adequate resources” are very subjective – and the contractor will interpret them very differently to the owner.

  

However, these assumptions are usually accepted without question, even though we all know that standards of supervision and quality management (not to mention experience and integrity) can vary greatly between contractors - and no doubt design consultants too. So how does an owner ensure that a project is adequately designed and constructed – and at a fair price to all parties? 

 

The answer is that the owner must ensure that the requirements for design and construction are adequately specified – including the requirements for inspection – and that the construction processes are adequately inspected to ensure the construction (and inspection) requirements are complied with.. Everything depends on the project specification containing the necessary requirements – before tenders are invited. Obviously, this is much harder for design and build than for traditional contracts – but it is not impossible. This paper tries to address all the issues involved.

   

4.2 Adapting the Execution Standard to define inspection requirements

 

In the Execution Standard the requirements for quality management are specified in terms of three Execution Classes (1, 2 and 3).The required strictness increases from Class 1 to Class 3.

All concreting and related processes will require an Inspection Plan – particularly where major or complex pours are involved. The Inspection Plan will need to address at least the issues at each location to be inspected - as listed in Annex B of the Execution Standard. 

 

As the inspection regime for Execution Class 3 may incorporate a significant component of inspection / verification by the owner or his agents, in addition to more traditional quality control (QC) and quality assurance (QA) roles by the contractor, it is imperative that the Inspection Plan requirements be included in the preliminary tender documents prepared by the owner or by his professional team.  These requirements would therefore need to have been developed at least in outline form by tender stage. To achieve this, the owner or his professional team must have given adequate consideration to requirements for inspection and / or verification and / or supervision and to how these responsibilities will be borne by the various parties. Only in this way can the achievement of the desired quality and safety be assured.

 

The following stated requirements for an Inspection Plan (adapted from Appendix G) would be reasonably suitable for inclusion in an Interim Project Specification (IPS) for a D & B project:

“As part of the tender documentation an outline Inspection Plan is provided by the owner which specifies the supervision requirements for all critical processes and member types.  It designates how the responsibilities for inspection, monitoring and verification are to be distributed between the designer, the constructor and the owner, or their agents. 

 

Appropriate items are included in the tender schedule against which amounts are to be entered to provide for all supervision costs.  The schedule includes details and an estimate of the proposed supervision to be provided by the owner. 

 

The relevant members of the contractor’s project management team shall familiarise themselves with the potential problems identified by their design and construction personnel, and shall incorporate appropriate preventive actions in the procedures of the relevant components of the Project Quality Plan (PQP).  This would include as appropriate the Concreting Plan and associated sub-plans for Reinforcement, Formwork, Falsework and Post-tensioning. (The contractor’s PQP shall incorporate all problems and dangers identified by the owner in the IPS together with accompanying specified requirements and draft procedures, and these (with amendments as approved by the owner) shall be integrated into the relevant preventive procedures.

 

Progressively updated records shall be kept of the potential and actual construction problems associated with the design details, together with the methods adopted to eliminate or minimise them”.

 

 

5 Inspectors, Construction Auditors and (Independent) Project Verifiers

The traditional role of an inspector (or an inspecting engineer) must be drastically upgraded. Inspectors will need to be formally qualified in the range of construction processes in which they intend to specialise. Some inspectors will need to be competent in the control of processes such as tack welding, post-tensioning and the erection of falsework. They (or their colleagues) will also need to be competent in the examination of specifications and documented technical procedures. They will need to be able to ask and answer questions such as:

Inspectors may work at different times for owners, contractors or consultants – or for independent verifiers who may be employed by any of those parties. Some inspectors may be required to carry out continuous monitoring of a particular process over an extended period. Others may be required to carry out focused inspections involving a few hours or days, with the purpose of verifying that specified procedures are being followed.

Such focused inspections are in fact audits – and these inspectors may be referred to as “construction auditors”. Construction auditors should form the nucleus of a Project Verifier’s organisation. The construction auditor must also be involved in the design detailing process Audits should always be focused on identifying potential problems or dangers – they should not take the random approach normally associated with quality auditors and ISO 9001:2000.

Click image to enlarge

 

6 How to reduce the risk of more falsework collapses like Can Tho

In July, 2008, after an 8 month investigation into the falsework collapse on Can Tho Bridge, Vietnam’s Construction Minister, Nguyen Hong Quan, announced the findings. In this paper, it is only possible to quote the most comprehensive newspaper report that could be found in English.

One of the most enlightening early reports was from News 24 Com (South Africa) 080703

"The uneven sinking limited to the foundation of a temporary pillar is considered an unfortunate circumstance that is difficult to foresee in normal designing," the newspaper quoted the commission's report as saying.

Soil-drilling tests of the foundation found soft sand in one sample and relatively solid sand in the other, which left the pillar lopsided and later resulted in bolts and crossbars breaking and a domino collapse of the bridge, the newspaper quoted the report as saying.

Asked whether the accident could have been prevented if the contractors had performed the drill tests prior to setting the pillar, Quan said even American construction standards do not require multiple soil drilling tests for one temporary pillar”.

Obviously, there are still many unanswered questions. Hopefully, more details will be provided soon. For the present, this paper poses the question, what would you do if you were a construction auditor – let us say an independent project verifier – commissioned by the owner to audit the design and construction of a similar bridge project which is about to commence?

It would take another paper to answer this question comprehensively. However, the prospective auditor is referred to Table 1 – and Item 2-S1(b) – to find typical questions which should be asked of the investigation and design teams, (and which should be documented in the IPS and FPS). Typical questions for the construction team can be found in Items 5-PS (a) & (b) – particularly question (b)(i).

As has been explained, there may be deficiencies in the requirements contained in the FPS for a D & B contract if they weren’t adequately presented in the IPS. To correct such a situation will probably require the owner to make extra payments, and the auditor may have to stand firm to ensure that all parties meet their responsibilities. However, if the auditor perseveres with his questions until they are answered satisfactorily, then he will have fulfilled his responsibilities to himself, his employer, and all the parties involved in the project – including the workers whose lives he may have saved.

  

 

7 Conclusion - the need for a new culture of project management

 

This paper calls for a response from the international engineering fraternity which will require a departure from long established – but inadequate – procedures of project management and reliance on standard specifications which don’t effectively address the issues of quality and safety on engineering construction projects. It also requires building bridges of understanding and trust among owners, consultants, contractors and subcontractors and their employees. These bridges will be particularly important where, historically, there have been distrust and an adversarial culture.

This paper closes with a definition from the Bible – written 2000 years ago but still relevant today. It is a definition of the phrase “true religion” one that should be generally acceptable – even to individuals and societies that claim to be atheist. The definition is as follows:

“Pure and undefiled religion before God and the Father is this:

(i)       to visit orphans and widows in their trouble, and

(ii)     to keep oneself unspotted from the world.”

There are two parts to this definition. The first part has been demonstrated to the world by the Chinese Government and people in their response to the plight of the victims of the Sichuan earthquake. (The whole world was powerfully impacted by the images we saw on television – from Premier Wen Jiabao to the soldiers of the People’s Liberation Army as they responded with compassion to the suffering of their people.) The second part is particularly relevant to the thrust of this paper. It also appears to be a driving motivation for the recent Construction Law promulgated by the PRC Ministry of Construction.

With regard to part (i), engineers can demonstrate their compassion for the people by making sure that structures don’t fall down – either during construction or in service. But part (ii) is even more relevant to engineers and the thrust of this paper. “To keep oneself unspotted from the world” means to be resistant to corruption - and corruption is not just the acceptance of bribes. It includes the more subtle pressures which may be exerted to neglect essential investigation work so as to save time and cut costs. To “keep oneself unspotted” may make us unpopular - and even cause us to lose our jobs.

I trust that there will be engineers in China and Australia and many other nations that will work together to establish a new culture of contract management. The initial costs will be substantial, but they will be far outweighed by the eventual financial benefits - not to mention the benefits to our communities and nations by preventing future disasters.

 

Table 1

(Version 1 080815)

   

Item No
& Code

Description

 

  

Typical Questions to be asked (and answered) by Construction Auditors, to verify that the contractor is complying with the Owner's requirements.

 

 

Note: Items 1 & 2 below should be carried out by (or on behalf of) the Owner before tenders are invited.

 

1 - CD

Concept Design

(i) Is proposed method of construction practical and reasonably economical?

 

 

2 - SI (a)

Site Investigation
(Permanent Works - locations for piers & abutments)

(i) Are there sufficient bore results; do they go deep enough; and are they consistent enough to enable the underlying foundation profile to be reliably plotted on either side of the bridge footprint (plan of deck)?

 
(ii) If there were discontinuities in the preliminary results, have additional bores been taken to ensure that discontinuities are accurately located?

 
(iii) Does the final plotted profile of the foundation layers make good sense?

 
(iv) Does the test boring/sampling subcontract provide for extra locations to be bored/tested until underlying profile can be reliably plotted?

 
(v) Has this work been adequately inspected while in progress?

 

 

2 - SI (b)

Site Investigation
(Temporary  Works e.g. Falsework)

Questions to be asked (preferably) before tenders are invited

 
(i)
Does the foundation profile obtained for locating the permanent works provide adequate information to justify a design concept incorporating cast in place concrete spans to be temporarily  supported from the ground?

 
(ii) Are the upper layers of the foundation profile so variable (e.g. interlayering of sand and clay lenses) that the risk of differential settlement may require (some) temporary supports to be underpinned by short piles?


Questions to be asked of contractor during his preparation of falsework plan


(iii) If piling is not proposed, have sufficient bearing tests been carried out to verify relative uniformity of ground support?

 
(iv) If differential settlement is still considered an acceptable risk, is there a plan for installing load cells under selected falsework supports to monitor variations in loads both during and after the concrete decks are poured?

 

  

Items 4 & 5 below apply directly only to traditional contracts; (where the design and the project specification are prepared by the Owner or its consultant) and the contractor tenders on the basis of a completed set of drawings and associated specifications - which later become the contract documents.


To apply the principles of Items 4 & 5 to the increasingly common Design & Build type contracts, it is necessary to think in terms of an Interim Project Specification (IPS) - which is usually prepared by the Owner's design consultant; and a Final Project Specification (FPS) - which is prepared by the contractor's design consultant (The FPS should comply with all the requirements included in the IPS.) [Refer to Section 3 of Paper - also Section 5]

 

 

4 - DD

Design Details

(i) Are there detailed reinforcement drawings (preferably 3-D) of all areas of heavily congested reinforcement, confirming that bars as detailed can be placed without conflict or loss of cover?


(ii) For deep pours (e.g. pile caps), have the proposed locations of concrete discharge points been shown on the drawings, and can it be confirmed that concrete of the required properties can drop cleanly through the reinforcement  cage, and then flow laterally to produce full compaction in all cover zones?

 

 

5 - PS (a)

Project Specification (a) Preventive Procedures for Construction Processes

(i) Are all major construction processes clearly identified, together with their potential problems and dangers - and are there effective

 requirements to ensure the contractor submits documented procedures to explain "how" these potential problems and dangers will be minimised?


(ii) Is it clearly stated in relation to each process, that the contractor must confirm that these requirements have been incorporated in the relevant subcontracts (whether signed before or after the main contract), and that the costs of implementing effective preventive procedures have been allowed for in the subcontractor's price?

 

 

5 - PS (b)

Project Specification (b)
Inspection Procedures & Costs

(i) Is there a requirement for each major process that the contractor must also submit documented procedures to explain how the construction process will be inspected and verified as the process is carried out.(The construction and inspection procedures may be combined in one document)


(ii) Is it clearly stated that the contractor's inspection procedures must comply with the specified inspection requirements, including the inspector's qualifications, in what location and for what time period the inspections will be carried out - and which party is responsible for providing the inspector?


(iii) Does the tender schedule of items, rates and amounts include separate items for each process inspection, and provision to separate the costs assigned to each party?